Heater-cooler devices are often necessary for use during surgeries to warm or cool patients as part of their care. They are especially important tools for surgeries involving the heart and lungs (cardiothoracic surgeries). Heater-cooler devices, as shown below in Figure 11, include tanks that provide temperature-controlled fluid (usually water) to external heat exchangers or to warming/cooling blankets through closed water circuits.
Figure 1: Heater-cooler device Pathways
Figure 1 is a schematic representation of heater-cooler circuits during cardiac surgery. The blue arrows at the top of the image indicate cold fluid flow from the heater-cooler to a heat exchanger, and temperature-controlled cardioplegia solution from the heat exchanger to the patient. The red arrows on the bottom left-side of the image indicate warm fluid flow from the heater-cooler to a heat exchanger, and temperature-controlled patient blood flow from a heat exchanger to the patient.
- Blue arrows identify the cardioplegia circuit and show cardioplegia solution entering the “heart lung machine.” to exchange heat with the temperature-controlled heater-cooler fluid. Cardioplegia is used to stop the heart during surgery.
- Rectangles with zigzag lines are heat exchange coils. They separate heater-cooler fluid flow from patient blood flow and the cardioplegia solution (for example: the fluid in the heater-cooler device is isolated from the patient, cardioplegia solution, and blood circuits).
- Red arrows identify the patient blood circuit and show warm heater-cooler fluid flow and patient blood flow.
Heater-cooler devices are Class II devices that can be cleared under one of the following cardiovascular classification regulations:
- 870.4250 Cardiopulmonary Bypass (CPB) Temperature Controller
- 870.5900 Thermal Regulating System
The CPB Temperature Controller is intended to supply temperature-controlled fluid to heat exchangers associated with devices (for example, blood oxygenators) intended to keep circulating blood and organs at a specific temperature best suited to the type of surgery being performed. Thermal Regulating Systems are generally cleared for use with warming/cooling blankets. Although heater-cooler devices fall under the cardiovascular classification regulations, they may be used during a variety of medical procedures.
These web pages:
- Contain information and resources for patients
- Clarify the FDA’s recommendations to health care providers and staff at health care facilities to help minimize patient risks of infections associated with water-based heater-cooler devices
- Include resources2 that may help in assessing and mitigating risks to patients.
1 Sommerstein R, Rüegg C, Kohler P, Bloemberg G, Kuster SP, Sax H. Transmission of Mycobacterium chimaera from Heater–Cooler Units during Cardiac Surgery despite an Ultraclean Air Ventilation System. Emerg Infect Dis. 2016 June;22(6):1008-13. http://wwwnc.cdc.gov/eid/article/22/6/16-0045_article
2 Weeks, J. W., Segars, K., & Guha, S. (2020). The Research Gap in Non-tuberculous Mycobacterium (NTM) and Reusable Medical Devices. Frontiers in public health, 8, 399. https://doi.org/10.3389/fpubh.2020.00399